Question

10g of ice at melting point is added to 100g of
water at 30°C in a copper calorimeter of mass 10 g.
The final temperature is 20°C. Calculate the value
of latent heat of fusion of ice. L
S.H.C. of water = 4.2J g.1°C-1 and S.H.C. of copper
= 0.4J 3-1 °C-1
​

Answer 1

Explanation:

ANSWER

Here, Mass of water m

w

=100g

Mass of ice, m

i

=10g

Specific heat of water,S

w

=1calg

−1

o

C

−1

Latent heat of fusion of ice,L

fi

=80calg

−1

Let T be the final temperature of the mixture.

Amount of heat lost by water

=m

w

s

w

(△T)

w

=100×1×(50−T)

Amount of heat gained by ice

=m

i

L

fi

+m

i

s

w

(△T)

i

=10×80+10×1×(T−0)

According to principle of calorimetry:

Heat lost = Heat gained

100×1×(50−T)=10×80+10×1×(T−0)

500−10T=80+T

11T=420orT=38.2

o

C